1. Field
Example embodiments relate to cutting tools for dentistry, general surgery, veterinary medicine, etc. More particularly, example embodiments relate to cutting tools including a shank portion and a cutting portion including a dual structure of material and composition such that material of main body is reduced, economic feasibility is enhanced, easy detachability is obtained, strong coherence is obtained in a combination mode, durability and a cutting force increase, friction heat decreases, and tissue damage by friction heat of a cutting edge portion is prevented.
2. Description of the Related Art
Recently, implant procedures in a dental procedure of a medical procedure universally are prevalent. In the implant procedures, an artificial tooth fixture having a screw shape and including titanium is implanted to be amalgamate with a bone in a region at which a tooth is removed, and then a connection member such as an abutment is combined, and then a prosthetic appliance such as a crown is fixed such that an original ability of a tooth is recovered.
FIG. 1 is a cross-sectional view illustrating an example of a conventional medical cutting tool.
As illustrated in FIG. 1, a perforation drill 1 is used in an implant dental procedure to perforate an alveolar bone to implant an artificial tooth.
In using the conventional perforation drill 1 having a metal material, the perforation drill 1 having a proper diameter corresponding to an implant procedure situation must be used and a perforation procedure must be operated carefully such that a damage of a bone tissue by a friction heat is prevented. In the perforation procedure, when the friction heat at a cutting edge portion 3 increases, a bone tissue of a tooth is damaged by the friction heat. The friction heat must be less than a human temperature such that easy osseointegration after an implantation at the alveolar bone is obtained.
Conventionally, a rotation RPM (rotation per minute) of a cutting tool is controlled to reduce the friction heat. In a first step of a perforation procedure by using a perforation drill, a perforation hole is made at an implant region at a rotation RPM which is within a range of about 1000 RPM to about 1500 RPM under 35 NCm torque, and in a second step, another perforation drill of which diameter is substantially greater than a diameter of the perforation drill is used at a rotation RPM which is within a range of about 500 RPM to about 800 RPM or about 300 RPM to about 400 RPM to reduce the friction heat.
However, the implant procedure depends on a personal skill of an operator, and the bone tissue is damaged by the friction heat such that it results in a bad osseointegration of an implant.
In the conventional perforation procedure, a coolant such as a cool saline solution is sprayed to reduce the friction heat of the cutting tool.
However, the saline solution as the coolant and a powder generated in the perforation procedure can be swallowed by a patient such that the use of the saline solution is limited and the friction heat of the cutting edge portion 3 cannot be cooled enough.
The cutting tool such as the perforation drill in the conventional implant procedure includes a stainless steel (medical grade) drill which is not rusty and hygienic. However, by a high thermal conductivity of the cutting tool such as the stainless steel (medical grade) drill, a friction heat greater than a human temperature is generated when an implant or an fixture is inserted in the alveolar bone, and then the coolant is necessary in the implant procedure.
When the cutting tool such as the stainless steel (medical grade) drill is used in the implant procedure, the friction heat at a high temperature can be transferred into a neuron of the alveolar bone and a necrosis of the neuron occurs. A bad osseointegration and loosening after the implant procedure can occur.
Though the stainless steel (medical grade) drill as the convention cutting tool is hygienic, a surface of the cutting tool becomes rusty by frequent cleaning and disinfection due to repeated use. Some patients may have an allergy to a metal material such as stainless steel (medical grade). Additionally, by the high thermal conductivity of the stainless steel (medical grade) drill, though the saline solution is used as a coolant, the friction heat is not cooled easily such that a bone tissue is damaged by the friction heat.
In order to solve the problems, instead of the stainless steel (medical grade) drill, a zirconia (ceramic) drill is used in the implant procedure, recently.
The zirconia (ceramic) drill has chemical resistance, corrosion resistance and bioaffinity such that a side affect such as an allergy to a metal material does not occur. And a perforation procedure by using the zirconia (ceramic) drill has a high cut efficiency and a low friction coefficient such that a lower friction heat than a friction heat by the stainless steel (medical grade) drill is generated and a perforation procedure without a coolant is possible.
However, the conventional zirconia (ceramic) drill is brittle. Particularly, a shank portion and a cutting edge portion is manufactured integrally such that the shank portion is easily broken when the shank portion is connected to a handpiece of the high speed rotation apparatus or when the shank portion is rotated at a high RPM, and a boundary between the shank portion and the cutting edge portion is broken.
Additionally, the conventional zirconia (ceramic) drill is manufactured by a powder compression sintering method such that a manufacture cost is high and the use of the integrated zirconia (ceramic) drill is limited. In a dental clinic, the use of the zirconia (ceramic) drill of which cost is greater than a cost of the stainless steel (medical grade) drill is avoided, and it is difficult that the zirconia (ceramic) drill having much advantage is distributed widely.
Korean Utility Registration No. 20-0434629 and Korean Utility Registration No. 20-0300750 are prior arts.
Accordingly, a new dental cutting tool having a low friction heat and a high durability is needed.